Conventionally, the reducing gas utilized in a shaft furnace for the direct reduction of iron is first reformed outside of the shaft furnace (e.g. in a reformer). More recently, however, there has been a trend towards utilizing a zero reformer, no reformer, or reformerless process that eliminates or substantially reduces the need for external reforming, opting instead for reforming in the shaft furnace itself combined with the direct reduction process. Some amount of external reforming may, however, occur outside of the shaft furnace, but such external reforming is often minimal and only to supplement the need for reforming gas.
One inherent problem with this approach is the inefficiency in creating an even burden uniformity within the shaft furnace or reactor as is created with external reforming, such that reforming is maximized and direct reduction takes place uniformly. Typically, in a shaft furnace, the gravity fed downwards flow of the burden is faster through the center of the shaft furnace than it is along the sides, for example. This results in both undesirable and inconsistent reforming and direct reduction gradients. This problem is compounded as the diameter of the shaft furnace increases.
In conventional direct reduction systems, utilizing an external reformer, unique iron oxide feeding to the top of the shaft furnace, a plurality of rotating mixing shafts or the like, and/or a stationary flow aid are used in the shaft furnace to eliminate undesirable direct reduction gradients, minimize burden clumping, etc., i.e. to promote desirable physical and chemical characteristics. To date, however, such mechanisms have not been used in a zero reformer, no reformer, reformerless, or minimal reformer process in the reforming and/or direct reduction zones. These mechanisms are the subject of the present invention.